X86: integrate CMA with DMA-mapping subsystem

This patch adds support for CMA to dma-mapping subsystem for x86
architecture that uses common pci-dma/pci-nommu implementation. This
allows to test CMA on KVM/QEMU and a lot of common x86 boxes.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 16 insertions, 2 deletions

diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 3003250ac51d..62c9457ccd2f 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -100,14 +100,18 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
                                  struct dma_attrs *attrs)
 {
         unsigned long dma_mask;
-        struct page *page;
+        struct page *page = NULL;
+        unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
         dma_addr_t addr;
 
         dma_mask = dma_alloc_coherent_mask(dev, flag);
 
         flag |= __GFP_ZERO;
 again:
-        page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
+        if (!(flag & GFP_ATOMIC))
+                page = dma_alloc_from_contiguous(dev, count, get_order(size));
+        if (!page)
+                page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
         if (!page)
                 return NULL;
 
@@ -127,6 +131,16 @@ again:
         return page_address(page);
 }
 
+void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
+                               dma_addr_t dma_addr, struct dma_attrs *attrs)
+{
+        unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+        struct page *page = virt_to_page(vaddr);
+
+        if (!dma_release_from_contiguous(dev, page, count))
+                free_pages((unsigned long)vaddr, get_order(size));
+}
+
 /*
  * See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel
  * parameter documentation.